Bladder tumors induced by the carcinogen N-(4-(5-nitro-2-furyl)-2-thiazolyl) formamide (FANFT) resemble their human counterpart both grossly and histologically and appear to be an excellent model to evaluate the effect of chemotherapeutic agents. One of these transitional cell tumors has been serially transplanted and is used to screen new drugs and combinations for antitumor activity. The most active single drugs are cytoxan and cis-platinum. The best combination is cytoxan and adriamycin. Irradiation is currently being explored in this model to determine the optimal treatment schedule. Early data suggest an additive effect between irradiation and chemotherapy. Intravesical chemotherapy has been evaluated by determining which drugs are capable of inhibiting the implantation of transitional tumor cells in the murine bladder. Since tumor cell implantation might be a factor in the high local recurrence rate of human bladder cancer, irrigation with an effective cytotoxic agent might reduce this incidence. Intravesical Epodyl and epipodophyllotoxin (VM-26) significantly reduced the incidence of tumor cell implantation in the animal model. Thio-tepa exhibited moderate antitumor activity. Systemic cytoxan initiated as late as 10 days post tumor instillation prevented implantation. It is important to note that there has been a close correlation between clinical response rates to antitumor drugs and their activity in this animal model. It is hoped that information gained from these animal models, which allow evaluation of many drugs within a relatively short period of time, will continue to identify drugs effective in transitional cell carcinoma with the intention of stimulating therapeutic trials in patients with bladder cancer. BIBLIOGRAPHIC REFERENCES: Soloway, M.S. and Martino, C.: Long Term Chemotherapy and/or Immunotherapy of Primary Murine Bladder Cancer. Proc. Am. Assoc. Cancer Res., 17:9, 1976.